This invention relates to gas discharge lasers, and more particularly to a pulsed power supply for a gas discharge laser.
A CO.sub.2 laser power supply has to be capable of initiating and maintaining a glow discharge in a mixute of CO.sub.2, helium and nitrogen at a pressure of 20 torr. Typically, the voltage required for ionization is approximately 20,000 volts per meter while that required to sustain the discharge current at 50 milliamperes is approximately 10,000 V/m.
If a single supply is used to drive a 11/2 meter laser tube, it would have to be able to deliver 30,000 V at 50 mA despite the fact that it will normally only need to deliver 15,000 V at 50 mA. In some prior art circuits a second power supply is connected in parallel with the first power supply in order to provide the initial higher voltage to ionize the tube. Such circuits are discussed in U.S. Pat. Nos. 3,491,309, 3,532,930, 3,588,740 and 3,842,365.
All hitherto prior art circuits of this type suffer from the disadvantages that they are inherently unreliable in being triggered, they are relatively complex to design for specific frequencies and laser tube lengths, and they contain more materials and parts than are desirable.